Study on the cephalopelvic relationship with cephalic presentation in nulliparous full-term Chinese pregnant women by MRI with three-dimensional reconstruction.

Purpose: To analyze the relationship between fetal head size and maternal pelvis size using magnetic resonance imaging (MRI) with a 3-D reconstruction technique.

Methods: A total of 301 nulliparous full-term Chinese pregnant women with cephalic presentation were enrolled and received MRI examinations before labor onset. Data were collected and imported into Mimics software to reconstruct the maternal pelvis and fetus.